Direct Red 80 (Sirius Red) is a polyazo dye primarily used in staining methods for collagen and amyloid. Direct Red 80 does not release benzidine as it degrades. Direct Red 80 is safer than many traditional direct dyes.

Physicochemical Properties

Molecular Formula	C45H26N10NA6O21S6
Molecular Weight	1373.07
Exact Mass	1371.9
CAS #	2610-10-8
Related CAS #	25188-41-4 (Parent)
PubChem CID	75783
Appearance	Brown to reddish brown solid powder
Density	1.85 g/cm3
LogP	14.765
Hydrogen Bond Donor Count	4
Hydrogen Bond Acceptor Count	29
Rotatable Bond Count	10
Heavy Atom Count	88
Complexity	2790
Defined Atom Stereocenter Count	0
InChi Key	YIQKLZYTHXTDDT-UHFFFAOYSA-H
InChi Code	InChI=1S/C45H32N10O21S6.6Na/c56-43-33-13-5-27(17-23(33)19-39(81(71,72)73)41(43)54-52-35-15-7-29(21-37(35)79(65,66)67)50-48-25-1-9-31(10-2-25)77(59,60)61)46-45(58)47-28-6-14-34-24(18-28)20-40(82(74,75)76)42(44(34)57)55-53-36-16-8-30(22-38(36)80(68,69)70)51-49-26-3-11-32(12-4-26)78(62,63)64;;;;;;/h1-22,56-57H,(H2,46,47,58)(H,59,60,61)(H,62,63,64)(H,65,66,67)(H,68,69,70)(H,71,72,73)(H,74,75,76);;;;;;/q;6*+1/p-6
Chemical Name	hexasodium;4-hydroxy-7-[[5-hydroxy-7-sulfonato-6-[[2-sulfonato-4-[(4-sulfonatophenyl)diazenyl]phenyl]diazenyl]naphthalen-2-yl]carbamoylamino]-3-[[2-sulfonato-4-[(4-sulfonatophenyl)diazenyl]phenyl]diazenyl]naphthalene-2-sulfonate
HS Tariff Code	2934.99.9001
Storage	Powder-20°C 3 years 4°C 2 years In solvent -80°C 6 months -20°C 1 month Note: Please store this product in a sealed and protected environment, avoid exposure to moisture.
Shipping Condition	Room temperature (This product is stable at ambient temperature for a few days during ordinary shipping and time spent in Customs)

Biological Activity

ln Vitro	The staining of collagen in saturated aqueous picric acid solutions and the staining of amyloid in alkaline solutions are two crucial applications of Direct Red 80 (Sirius Red) in histopathology. The building is reddened [1]. Following Direct Red 80 labeling, collagen synthesis and distribution were assessed using confocal laser microscopy (CLM). Different forms of collagen do not affect Direct Red 80's effectiveness. The samples were diluted with 0.1% Direct Red 80 in saturated aqueous picric acid acid, rinsed in ddH2O, then prepped with 0.2% phosphomolybdic acid (PMA) solution for 40 minutes. After that, they were incubated for 30 minutes. Lastly, 0.01 M HCl was used to wash each sample for two minutes. Colorless cytoplasm is prepared using PMA, and non-specific staining is removed with HCl [1].
References	[1]. Certification procedures for sirius red F3B (CI 35780, Direct red 80). Biotech Histochem. 2011;86(3):133-139.
Additional Infomation	Sirius red F3B is an organic sodium salt resulting from the formal condensation of Sirius red F3B (acid form) with six equivalents of sodium hydroxide. A polyazo dye used principally in staining methods for collagen and amyloid. It has a role as a fluorochrome and a histological dye. It contains a Sirius red F3B(6-).

Solubility Data

Solubility (In Vitro)

DMSO: < 1 mg/mL

Solubility (In Vivo)

Note: Listed below are some common formulations that may be used to formulate products with low water solubility (e.g. < 1 mg/mL), you may test these formulations using a minute amount of products to avoid loss of samples. Injection Formulations (e.g. IP/IV/IM/SC) Injection Formulation 1: DMSO : Tween 80： Saline = 10 : 5 : 85 (i.e. 100 μL DMSO stock solution → 50 μL Tween 80 → 850 μL Saline) *Preparation of saline: Dissolve 0.9 g of sodium chloride in 100 mL ddH ₂ O to obtain a clear solution. Injection Formulation 2: DMSO : PEG300 ：Tween 80 : Saline = 10 : 40 : 5 : 45 (i.e. 100 μL DMSO → 400 μLPEG300 → 50 μL Tween 80 → 450 μL Saline) Injection Formulation 3: DMSO : Corn oil = 10 : 90 (i.e. 100 μL DMSO → 900 μL Corn oil) Example: Take the Injection Formulation 3 (DMSO : Corn oil = 10 : 90) as an example, if 1 mL of 2.5 mg/mL working solution is to be prepared, you can take 100 μL 25 mg/mL DMSO stock solution and add to 900 μL corn oil, mix well to obtain a clear or suspension solution (2.5 mg/mL, ready for use in animals). Injection Formulation 4: DMSO : 20% SBE-β-CD in saline = 10 : 90 [i.e. 100 μL DMSO → 900 μL (20% SBE-β-CD in saline)] *Preparation of 20% SBE-β-CD in Saline (4°C，1 week): Dissolve 2 g SBE-β-CD in 10 mL saline to obtain a clear solution. Injection Formulation 5: 2-Hydroxypropyl-β-cyclodextrin : Saline = 50 : 50 (i.e. 500 μL 2-Hydroxypropyl-β-cyclodextrin → 500 μL Saline) Injection Formulation 6: DMSO : PEG300 : castor oil : Saline = 5 : 10 : 20 : 65 (i.e. 50 μL DMSO → 100 μLPEG300 → 200 μL castor oil → 650 μL Saline) Injection Formulation 7: Ethanol : Cremophor : Saline = 10： 10 : 80 (i.e. 100 μL Ethanol → 100 μL Cremophor → 800 μL Saline) Injection Formulation 8: Dissolve in Cremophor/Ethanol (50 : 50), then diluted by Saline Injection Formulation 9: EtOH : Corn oil = 10 : 90 (i.e. 100 μL EtOH → 900 μL Corn oil) Injection Formulation 10: EtOH : PEG300：Tween 80 : Saline = 10 : 40 : 5 : 45 (i.e. 100 μL EtOH → 400 μLPEG300 → 50 μL Tween 80 → 450 μL Saline) Oral Formulations Oral Formulation 1: Suspend in 0.5% CMC Na (carboxymethylcellulose sodium) Oral Formulation 2: Suspend in 0.5% Carboxymethyl cellulose Example: Take the Oral Formulation 1 (Suspend in 0.5% CMC Na) as an example, if 100 mL of 2.5 mg/mL working solution is to be prepared, you can first prepare 0.5% CMC Na solution by measuring 0.5 g CMC Na and dissolve it in 100 mL ddH2O to obtain a clear solution; then add 250 mg of the product to 100 mL 0.5% CMC Na solution, to make the suspension solution (2.5 mg/mL, ready for use in animals). Oral Formulation 3: Dissolved in PEG400 Oral Formulation 4: Suspend in 0.2% Carboxymethyl cellulose Oral Formulation 5: Dissolve in 0.25% Tween 80 and 0.5% Carboxymethyl cellulose Oral Formulation 6: Mixing with food powders Note: Please be aware that the above formulations are for reference only. InvivoChem strongly recommends customers to read literature methods/protocols carefully before determining which formulation you should use for in vivo studies, as different compounds have different solubility properties and have to be formulated differently.  (Please use freshly prepared in vivo formulations for optimal results.)

Preparing Stock Solutions		1 mg	5 mg	10 mg
	1 mM	0.7283 mL	3.6415 mL	7.2829 mL
	5 mM	0.1457 mL	0.7283 mL	1.4566 mL
	10 mM	0.0728 mL	0.3641 mL	0.7283 mL

*Note: Please select an appropriate solvent for the preparation of stock solution based on your experiment needs. For most products, DMSO can be used for preparing stock solutions (e.g. 5 mM, 10 mM, or 20 mM concentration); some products with high aqueous solubility may be dissolved in water directly. Solubility information is available at the above Solubility Data section. Once the stock solution is prepared, aliquot it to routine usage volumes and store at -20°C or -80°C. Avoid repeated freeze and thaw cycles.